As with all writing about Iran’s political process, it is important to be humble about what we can know. Our sources of information about Iranian decision-making are miserable and the Iranian governmental process is labyrinthine and unpredictable even for the most subtle and knowledgeable observers inside Iran and out.
I believe that Iran’s interest in nuclear weapons is both wide and deep, but it is not adamantine. The issue, as always in politics, is not whether Iran wants to see its nuclear program through to completion but what it would be willing to sacrifice to keep it. On this matter, I believe the Iranians would be willing to sacrifice a fair amount, but hardly everything. What this suggests then is that convincing Iran to give up its nuclear program is going to require very considerable inducements, both positive and negative, but that it is not impossible to do so.
The key is for the United States and its allies to compel the Iranians to choose between their nuclear program and their highest priority—their economic well-being. The way of doing so is now well-explicated, including in my own work. Briefly, it would involve a multilateral sanctions regime that would gradually shut down Western (ideally the OECD, but initially perhaps just the G-7) investment in Iran, particularly its gas and oil sectors, in response to continued Iranian recalcitrance. Even with oil prices above $60 per barrel, Iran is desperate for Western investment capital because corruption is sucking the oil revenues right out of the system and thus having little impact on the overall economy. Despite the claims of some that Russia and China could make up for any loss capital from Europe and Japan, the fact is that their economies are still roughly a decade away from being in a position to do so.
We always knew that convincing states like Iran that have a range of important rationales for pursuing a nuclear capability to give it up is difficult. But few things in the worlds of politics and diplomacy are impossible, and there is good reason to believe that Iran can be dissuaded from its current course if the United States and its allies in Europe and Asia can forge a common position and make clear to Iran that pursuit of a nuclear weapon will cost it what most Iranians value the most.